According to the US Energy Information Administration (EIA, 2007), world energy-related CO2 emissions in 2004 were 26,922 million metric tons and increased 26.7% from 1990. As a result, atmospheric levels of CO2 have increased by about 25% over the past 150 years. Thus, it has become increasingly important to develop new technologies to reduce CO2 emissions.
The world is also facing costly gas and oil and limited reserves of these precious resources. Biofuels have been recognized as an alternative energy source. While efforts have been made to improve various production, further developments are needed.